Long lasting antibiotic composition comprising the 3-palmitic ester of thiamphenicol

ABSTRACT

THE INVENTION PROVIDES NEW THIAMPHENICOL SATLS COMPRISED IN THE GENERAL FORMULA:   (4-(CH3-SO2-)PHENYL)-CH(-OH)-CH(-NH-CO-CH(-CL)2)-CH2-   OOC-R   WHEREIN R IS AN ALKYL RADICAL COMPRISING FROM 13 TO 17 CARBON ATOMS. THE NEW SALTS ARE CHARACTERIZED BY A MUCH MORE LONG-LASTING ACTIVITY THAN THIAMPHENICOL ALONE.

United States Patent U.S. Cl. 424312 1 Claim ABSTRACT OF THE DISCLOSUREThe invention provides new thiamphenicol salts comprised in the generalformula:

NHO o CHC12 HSO-S Oz-Q-CH-(EH-O H20 0 O-R d-threo wherein R is an alkylradical comprising from 13 to 17 carbon atoms. The new salts arecharacterized by a much more long-lasting activity than thiamphenicolalone.

This is a division of application Ser. No. 822,104, filed May 2, 1969,now US. Pat. No. 3,652,607.

The present invention refers to new thiamphenicol derivatives, which areparticularly useful for obtaining antibiotic compounds havinglong-lasting activity. In particular the invention refers to newcompounds comprised in the following general formula:

NHCOCHCh d-threo wherein R is an aliphatic radical comprising from 13 to17 carbon atoms, to the processes for their preparation as well as tothe therapeutic compositions which comprise the new compounds of theinvention.

It is known that the chloramphenicol is a broad-spectrum antibioticwidely used. However, since the chloramphenicol possesses a verydisagreeable and persistant taste, the esters thereof have been preparedby esterifying its hydroxyl in 3-position with aliphatic acids of highmolecular weight.

These esters (US. Pat. 2,662,906) present with respect tochloramphenicol only the advantage of being tasteless althoughmaintaining an unchanged activity.

As a matter of fact, Glazko, A. J. & Coll., Antibiotics & Chemiotherapy8, 516, (1958) have demonstrated that the hematic levels obtained afteroral supply of chloramphenicol and chloramphenicol palmitate are nearlyidentical and reach the maximum level within two hours, while nearlyentirely disappearing after eight hours. The palmitate is the mostwidely used ester among the prepared ones. It is also known that thethiamphenicol is at present widely used because of the advantages whichit presents with respect to the chloramphenicol: Kunin, C. M. andFinland, M., Proc. Soc. Exp. Biol. Chem. 103, 246, (1960), (therethiamphenicol is mentioned as Thiocymetin, which is a trademark of theWinthrop Labts.).

It has now been surprisingly found that the activity of thethiamphenicol esters, which have been obtained by esterification of thehydroxyl in 3-position with high molecular weight aliphatic acids, ismuch more long-lasting than that of thiamphenicol.

In particular it has been found that the hematic levels obtained esteroral administration of thiamphenicol reach, with a behavior quitesimilar to that of chloramphenicol and of chloramphenicol esters, themaximum value after 3,803,321 Patented Apr. 9, 1974 two hours and thendecrease rapidly; on the contrary when equivalent quantities of an esterof thiampenicol with a fatty acid, according to the present invention,are

administered, the hematic levels increase slowly and are still low aftertwo hours, then reach the maximum between the fourth and the eighth hourand maintain still good levels after 12 hours.

The advantage otfered by such a medicine at long-lasting activity isevident when considering that the 3-4 daily administrations required bythiamphenicol, may be reduced to one administration only.

Experiments have been performed with two groups of Wistar rats, eachgroup comprising 20 d albin rats of 200 g. average weight; these havebeen treated, by means of a gastric probe, with thiamphenicol or withthiamphenicol palmitate in the form of syrupy micro-suspensionscontaining 2% of a suitable surfactant, in the particular case Tween 80.

The first group received an oral dose of 200 mg./kg. of thiamphenicol,while the second one received 333 mg./ kg. of thiamphenicol palmitate,which dose is equivalent to 200 mg. of thiamphenicol. Five rats of eachgroup were killed by bleeding 2, 4, 8 and 12 hours respectively aftermedicine administration, and the blood serum was separated at +4 C. Thedetermination of the antibiotic amount in each of the obtained serumsamples was carried out in a microbiological way, according to themethod of the scalar broth-dilutions, using as test microorganism thePasteurella boviseptica Harvard which is sensitive to 0.25 mcg./rnl. ofthiamphenicol. The reading of M.I.C. (minimum inhibitory concentration)was performed by direct turbidimetry after 18 h. from incubation at 37C. The results obtained are reported in the following Table 1.

TABLE 1 Thiamphenicol concentrations in meg. for m1. of serum after oraladministration of thiamphenicol and thiamphenicol palmitateThiamphenicol 200 mg./ Thiamphenicol palmitate kg. drawing time in h.333 mg./kg. drawing time in h.

Hats 2 4 8 12 2 4 8 12 Mean 13 6 2.1 0.6 3. 9 5.1 5.4 2.4 =!=o.s- =|=0=l=0 i=0. =1=0.06 5:0.6 *0. 37 $0.37 5:0.37

Clinical experiences performed on men have confirmed the above reportedresults.

The compounds of the present invention may be prepared by reaction ofthe thiamphenicol with a compound of the formula: RCO--X wherein R is analiphatic radical having from 13 to 17 carbon atoms and X is OH, OCO-R,Cl, Br, O-COOC H under suitable conditions and in particular underconditions such as to allow the esterification of the hydroxyl in the3-position only, while maintaining unetfected the hydroxyl inl-position.

The reaction is preferably carried out letting the thiamphenicol toreact with a slight excess of the chloride of the desired fatty acid, inthe presence of alkaline or alkalineearth bicarbonate or of pyridine,trialkylamine, N-alkylanilines, N,N-dialkyl-anilines, at a temperaturecomprised between 15 and 50 C.

A non-limitative example is reported hereinafter for illustrativepurposes only.

EXAMPLE Preparation of thiamphenicol palmitate 1,000 g. (2.8 moles) ofthiamphenicol, 780 g. of pyridine and 2,500 g. of dimethylformamide areintroduced into a 4-necks, 3 l. flask provided with reflux cooler,stirrer, thermometer and separatory funnel.

A clear, colorless solution is obtained under strong stirring. 780 g.(2.84 moles) of palmitoyl chloride are added over 75 minutes, whilekeeping under stirring; nearly instantly a white precipitate separatesinamounts increasing as the addition of the palmitoyl chlorideincreases; the temperature rises from 22 to 36 C. As soon as theaddition is completed the mixture is poured into a glass containing 3liters of water. The white precipitate is collected by filtration undervacuum and washed with water until Clions and the pyridine smelldisappear. The product is dried in an air oven over 18 hours thusobtaining 1,435 g. of raw product having a M.P. l05'l09 C.

The raw product is placed in a 6 l. flask together with 840 g. of methylalcohol and 3,860 g. of isopropyl ether; the mixture is refluxed up tocomplete solution, then is cooled to 5 C. and allowed to crystallize for16-18 hrs.

The crystalline precipitate is collected by filtration under vacuum anddried at 50 C. in a stove with air circulation.

1,040 g. of thiamphenicol palmitate containing 59.9% of thiamphenicolare obtaied: M.P. l101l3 C., M. W. 594.66, [a] -=+18.5i0.5 (c.=l% inabsolute ethyl alcohol).

Spectrophotometric characteristics: a solution in 95% ethyl alcoholshows the following maxima:

225 m 226 mu (E =15.0) and 273 m (E =l3.'5) and the following minima:

251- -l m and 271:1mu

The prepared producis a white or slightly ivory microcrystalline powder,odorless and tasteless. It is very soluble in dimethylformamide andtetrahydrofuran; soluble in acetone, ethylacetate and ethanol;water-insoluble. When dry it is stable in air and light. Itswater-suspensions are stable when kept at nearly neutral pH.

Therapeutic directions and doses Thiamphenicol palmitate ..g 2.5Polyoxyethylenesorbitanmonooleate g 1.2 Sodium benzoate g 0.24 Methylp.oxybenzoate g 0.07 Propyl p.0xybenzoate ....g.. 0.01 Anhydrous sodiumcitrate g 0.06 Saccharose g 38.4 Flavor g 0.3 Distilled water q.s.a ml60 We describe hereinafter the procedure for preparing 45 liters ofsuspension (equivalent to 750 flasks each having a ml. capacity) of theabove indicated composition: 900 g. of polyoxyethylenesorbitanmonooleateare dissolved into 7 kg. of distilled water, the solution is poured intoa china jar of 50 liters capacity and the Whole is added with 1.8765 kg.of thiamphenicol palmitate, sieved through a sieve at 196 mesh/cm with/3 of the entire amount of methyl and propyl p.oxybenzoate and withglass pearls having a diameter of 3.S-5 mm. The jar is placed on asuitable roll-mill which is actuated up to obtainment of a satisfactorymicronization (average diameter of crystals lower than 4-6 1.) p

15 liters of distilled water are poured into a container graduated at 45liters, 28.8 kg. of sugar are added, the solution is kept boiling forsome minutes and then the remaining amount of methyl and propylp.0xybenzoate as well as the sodium benzoate are added; the solution ishot-filtered to eliminate extraneous materials. The content of the jaris directly poured in the syrup containing the flavor while filteringthrough buchner filter or filtering net, the glass pearls and the jarare washed with water and the washing waters are added to the syrup.

The pH is adjusted to 5.6-5.8 by means of monohydrate citric acid, acitrate butter is added, the volume is adjusted to 45 liters (or theweight to 56.475 kg.) by means of distilled water and the suspension ispassed through a suitable homogenizer. The syrup is subdivided intocontainers of 60 ml. capacity.

We claim:

1. A therapeutic antibiotic composition having long lasting activitywhich comprises an antibiotically effective amount of a compound of theformula NHC OCHCl:

d-threo and a therapeutically acceptable carrier.

References Cited UNITED STATES PATENTS 2,988,483 6/1961 Barsky et al424-312 3,227,735 1/ 1966 DeWitt et a1 260-4048 3,689,643 9/ 1972Plotnikotf 424-319 3,729,563 4/ 1973 Cash et a1. 424-308 3,701,82910/1972 Baretoleni 424-319 ALBERT T. MEYERS, Primary Examiner D. M.STEPHENS, Assistant Examiner UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent No. 3,803,321 Dated April 9,- 1-974 Inventor(s) UbertoMaria Teotino et a1 It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 1, line 7 0: Please write "after" instead of "ester" Column 2,line 47: At the bottom of Table l "i e.s. instead of "i o.s.

Column 2, line 58: "unaffected" instead of- "uneffected Column 2, line58: "in the l-po-" instead of "in l-po Column 2, line 62:"trialkylamines" instead of "trialkylamine" Column 3, line 8: "raises"instead of "rises" Column 3, line 12: before "CL-ions" please put "the"Column 3, line 31: "product is" instead of "producis" Column 3, line 44:"They" instead of "The y" Signed and sealed this 24th day of Sept-ember1974.

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents DRM PO-lOSO (10-69) USCOMM-DC 603764 69 fi U.S. GOVERNMENT PR NTNG OFFICE: l9! 0-36-334

